Skowhegan Area High School
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 Range- Range is the difference between the largest and smallest data points. Percentile- A method to rank data. If you are in the 90th percentile, that means that you scored better than 90% of all the people but not as well as the other 10% Quartile- Quartiles are values that divide a sample of data into four groups containing (as far as possible) equal numbers of observations. A data set has three quartiles. References to quartiles often relate to just the outer two, the upper and the lower quartiles; the second quartile is the median. The lower quartile is the data value a quarter way up through the ordered data set (25th percentile); the upper quartile is the data value a quarter way down through the ordered data set (75th percentile). Interquartile Range- This is the difference of Q1 and Q3, which accounts for 50% of the data. 5-Number Summary- A 5-number summary is especially useful when we have so many data that it is sufficient to present a summary of the data rather than the whole data set. It consists of 5 values: the most extreme values in the data set (maximum and minimum values), the lower and upper quartiles, and the median. A 5-number summary can be represented in a diagram known as a box and whisker plot. In cases where we have more than one data set to analyze, a 5-number summary is constructed for each, with corresponding multiple box and whisker plots. Mean Absolute Deviation- This is the arithmetic average deviation (without regard to plus or minus) of a value from the mean of a set of values. Transformations- This is the method to change data depending on the units of measure or other changes. Standard Deviation- This is a measure of variation equal to the square root of the mean of the squares of the deviations from the arithmetic mean of distribution.